1. Field of the Invention
The present invention relates to a method of printing on both sides of sheet without using a both side printing mechanism and an apparatus for use therewith.
2. Related Background Art
In order to perform the both side printing with an image output device, the printing of odd pages and the printing of even pages are separately performed. Namely, there is a method (so-called a manual both side printing) in which the printing of odd (or even) page is first performed on one side of a sheet, the operator reverses the sheet of one side printed paper and sets it on a sheet supply cassette of a printer, and subsequently the printing of even number (or odd number) page is performed on the other side of the sheet. Also, another method to obtain the both side recorded matter involves using a printer with a both side printing mechanism (e.g., a sheet reversing mechanism).
However, with the above conventional method, a both side printing mechanism such as a sheet reversing mechanism for printing the back side after printing the front side is needed, and to effect an appropriate recovery from the paper jam, it is necessary to hold data of the front and back sides in a memory inside the printer, which requires a larger capacity of memory than normally used. Therefore, there is a drawback that the apparatus is more expensive.
Also, in the above former method, after printing one face of sheet, if the paper jam occurs in printing the other side, the recovery from the paper jam can not be appropriately performed since the data printed on one face of jammed paper can not be reproduced.
It is an object of the present invention to provide an image output method and an apparatus for use therewith which is capable of readily effecting an appropriate recovery from the paper jam in the both side printing, using a printer without having a both side printing mechanism.
To accomplish the above object, the present invention is characterized by comprising memory means for storing print data, paper jam detecting means for detecting an occurrence of paper jam in a printer, print end detecting means for detecting that the printing of one page is ended in the printer, page location detecting means for detecting the location in the memory means for each page of print data stored in the memory means, selective page printing means for selectively outputting print data stored in the memory means to the printer in a unit of page, printing page instructing means for classifying the pages of print data stored in the memory means into two groups of front and back, and instructing the selective page printing means to output data of each group to the printer, and paper jam recovery means for instructing the selective page printing means to output print data of at least one side of a sheet where paper jam has occurred to the printer, when paper jam is detected by the paper jam detecting means.
To accomplish the above object, the present invention is characterized by further comprising paper jam detecting means for detecting an occurrence of paper jam in a printer, page location detecting means for detecting the location in the memory means for each page of print data stored in the memory means, selective page printing means for selectively outputting print data stored in the memory means to the printer in a unit of page, printing page instructing means for classifying the pages of print data stored in the memory means into two groups of front and back, and instructing the selective page printing means to output data of each group to the printer, paper jam page number input means for inputting the page number at which paper jam has occurred, and paper jam recovery means for instructing the selective page printing means to output print data of at least one side of a sheet corresponding to the page number to the printer, as well as receiving the page number from the paper jam page number input means, when paper jam is detected by the paper jam detecting means.